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Merge pull request #21 from petterreinholdtsen/gsmtap-be-structure

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Introduce ctypes based gsmtap header parser
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Oros42 2017-09-04 08:47:15 +02:00 committed by GitHub
commit 05c761de36
1 changed files with 43 additions and 11 deletions
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42
simple_IMSI-catcher.py
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@ -60,7 +60,8 @@ IMSI : https://fr.wikipedia.org/wiki/IMSI
Realtek RTL2832U : http://doc.ubuntu-fr.org/rtl2832u and http://doc.ubuntu-fr.org/rtl-sdr
"""
from scapy.all import sniff
import ctypes
from scapy.all import sniff, UDP
import json
from optparse import OptionParser
@ -250,9 +251,33 @@ class tracker:
if do_print:
self.pfields(str(n), self.str_tmsi(tmsi1), self.str_tmsi(tmsi2), None, str(self.mcc), str(self.mnc), str(self.lac), str(self.cell), p)
class gsmtap_hdr(ctypes.BigEndianStructure):
_pack_ = 1
# Based on gsmtap_hdr structure in <grgsm/gsmtap.h> from gr-gsm
_fields_ = [
("version", ctypes.c_ubyte),
("hdr_len", ctypes.c_ubyte),
("type", ctypes.c_ubyte),
("timeslot", ctypes.c_ubyte),
("arfcn", ctypes.c_uint16),
("signal_dbm", ctypes.c_ubyte),
("snr_db", ctypes.c_ubyte),
("frame_number", ctypes.c_uint32),
("sub_type", ctypes.c_ubyte),
("antenna_nr", ctypes.c_ubyte),
("sub_slot", ctypes.c_ubyte),
("res", ctypes.c_ubyte),
]
def __repr__(self):
return "%s(version=%d, hdr_len=%d, type=%d, timeslot=%d, arfcn=%d, signal_dbm=%d, snr_db=%d, frame_number=%d, sub_type=%d, antenna_nr=%d, sub_slot=%d, res=%d)" % (
self.__class__, self.version, self.hdr_len, self.type,
self.timeslot, self.arfcn, self.signal_dbm, self.snr_db,
self.frame_number, self.sub_type, self.antenna_nr, self.sub_slot,
self.res,
)
# return mcc mnc, lac, cell, country, brand, operator
def find_cell(x, t = None):
def find_cell(gsm, x, t = None):
# find_cell() update all following variables
global mcc
global mnc
@ -291,8 +316,8 @@ def find_cell(x, t = None):
0030 02
0040 f8 02 01 9c
"""
if gsm.sub_type == 0x01: # Channel Type == BCCH (0)
p=str(x)
if ord(p[0x36]) == 0x01: # Channel Type: BCCH (1)
if ord(p[0x3c]) == 0x1b: # Message Type: System Information Type 3
# FIXME
m=hex(ord(p[0x3f]))
@ -316,13 +341,20 @@ def find_cell(x, t = None):
def find_imsi(x, t=None):
if t is None:
t = imsitracker
# Create object representing gsmtap header in UDP payload
udpdata = str(x[UDP].payload)
gsm = gsmtap_hdr.from_buffer_copy(udpdata)
#print gsm
if gsm.sub_type == 0x1: # Channel Type == BCCH (0)
# Update global cell info if found in package
# FIXME : when you change the frequency, this informations is
# not immediately updated. So you could have wrong values when
# printing IMSI :-/
find_cell(x, t=t)
find_cell(gsm, x, t=t)
else: # Channel Type != BCCH (0)
p=str(x)
if ord(p[0x36]) != 0x1: # Channel Type != BCCH (0)
tmsi1=""
tmsi2=""
imsi1=""